Question

a) 3x=90
b) 2x+ 10 =70
c) 2x+80=3x
d) x+50= 3x+20

Answer 1

Resposta:

a) 30

b)30

c) 80

d) 15

Explicação passo-a-passo:

a) 3x=90

x= $\frac{90}{3}$=30

b) 2x+10=70

2x=70-10

2x=60

x=$\frac{60}{2}$=30

c) 2x+80=3x

2x-3x=-80

-1x=-80

(multiplica tudo por -1)

x=80

d)x+50=3x+20

x-3x= -50+20

-2x=-30

x=-30/-2= 15

Answer 2

Resposta:

a)

$3x = 90 \\ x = \frac{90}{3} \\ x = 30$

b)

$2x + 10 = 70 \\ 2x = 70 - 10 \\ 2x = 60 \\ x = \frac{60}{2} \\ x = 30$

c)

$2x + 80 = 3x \\ 2x - 3x = - 80 \\ - x = - 80 \: .( - 1) \\ x = 80$

d)

$x + 50 = 3x + 20 \\ x - 3x = 20 - 50 \\ - 2x = - 30 \: .( - 1) \\ 2x = 30 \\ x = \frac{30}{2} \\ x = 15$